An Isomünchnone-Based Method for the Synthesis of Highly Substituted 2(1H)-Pyridones
摘要:
1-(Benzenesulfonyl-diazoacetyl)-pyrrolidin-2-one was prepared by a diazo transfer of 1-(benzenesulfonylacetyl)-pyrrolidin-2-one with p-acetamidobenzenesulfonyl azide and triethylamine. Treatment; of the diazoimide with a catalytic quantity of rhodium(II) acetate resulted in the formation of an isomunchnone dipole, which underwent bimolecular trapping with various dipolarophiles in high yield. The initially formed cycloadducts were not isolable or observed, as they all readily underwent ring opening to give the 3-hydroxy-2(1H)-pyridone ring system. The 3-hydroxy-2(1H)-pyridones were readily converted to the corresponding triflates, which function as suitable substrates in various types of palladium-catalyzed cross-coupling reactions. Commercial tetrakis(triphenylphoshine)palladium was found to be a particularly effective catalyst for the cross-coupling with aryl, vinyl, and acetylenic partners. An application of the method to the synthesis of the indolizidine alkaloid (+/-)-ipalbidine was carried out in eight steps in 17% overall yield. The angiotensin-converting enzyme inhibitor (-)-A58365A was also synthesized by a process based on the [3 + 2]-cycloaddition reaction of a phenylsulfonyl substituted isomunchnone intermediate. The starting material for this process was prepared from L-pyroglutamic acid and involved using a diazo phenylsulfonyl substituted pyrrolidine imide. Treatment of the diazoimide with Rh-2(OAc)(4) in the presence of methyl vinyl ketone afforded a 3-hydroxy-2-pyridone derivative, which was subsequently converted to the ACE inhibitor in six additional steps.
Stereoselective synthesis of 2,4-disubstituted butanolides
作者:A. V. Lozanova、T. M. Ugurchieva、V. V. Veselovsky
DOI:10.1007/s11172-007-0021-4
日期:2007.1
A series of 2,4-disubstituted butanolides was prepared based on the trans-stereoselective electrophilic cyclization of substituted N-(pent-4-enoyl)pyrrolidines. The butanolides may be considered as synthons for this type of natural products.
作者:Yang Liu、Zhongyi Mao、Alexandre Pradal、Pei-Qiang Huang、Julie Oble、Giovanni Poli
DOI:10.1021/acs.orglett.8b01616
日期:2018.7.6
The synthesis of bi- and tricyclic structures incorporating pyrrolidone rings is disclosed, starting from resonance-stabilized acetamides and cyclic α,β-unsaturated-γ-oxycarbonyl derivatives. This process involves an intermolecular Tsuji–Trost allylation/intramolecular nitrogen 1,4-addition sequence. Crucial for the success of this bis-nucleophile/bis-electrophile [3 + 2] annulation is its well-defined
Ligand effects in the rhodium(II) catalysed reactions of diazoamides and diazoimides
作者:Soyfur Miah、Alexandra M.Z. Slawin、Christopher J. Moody、Scott M. Sheehan、Joseph P. Marino、Mark A. Semones、Albert Padwa、Ian C. Richards
DOI:10.1016/0040-4020(95)01070-x
日期:1996.2
ligands, fluorinated carboxamides strongly promoting attack on aromatic rings in preference to other processes. Decomposition of the diazoimides resulted in intramolecular attack on the carbonyl group to give an ylide which could be trapped inter- or intramolecularly. X-Ray crystal structures are reported for the diazo compounds 2 and 4, the indoles 17 and 25, the β-lactam 20, the cycloheptapyrrolones 24
A Base-induced Elimination Reaction of Phenylsulfonylacetates. I. General Aspect and Stereochemistry
作者:Akira Sera、Hiroshi Mano、Kazuhiro Maruyama
DOI:10.1246/bcsj.47.1754
日期:1974.7
t-butoxide in t-butyl alcohol. The intervention of a carbanion as an intermediate of the elimination was proposed. The stereochemistry of the elimination was examined by the use of erythro and threo-2-deuterio-1,2-diphenylethyl phenylsulfonylacetates. From the deuterium content in a product, i.e., trans-stilhene, the elimination was found to occur predominantly in a syn fashion.
The present invention relates to compounds useful in the modulation of potassium channel activity in cells, in particular the activity of Kv1.3 channels found in T cells. The invention also relates to the use of these compounds in the treatment or prevention of autoimmune and inflammatory diseases, including multiple sclerosis, pharmaceutical compositions containing these compounds and methods for their preparation.